Microsoft Security Bulletin MS13-027 - Important

Vulnerabilities in Kernel-Mode Drivers Could Allow Elevation Of Privilege (2807986)

Published: March 12, 2013 | Updated: July 09, 2013

Version: 1.2

General Information

Executive Summary

This security update resolves three privately reported vulnerabilities in Microsoft Windows. These vulnerabilities could allow elevation of privilege if an attacker gains access to a system.

This security update is rated Important for all supported releases of Microsoft Windows. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerabilities by by correcting the way that a Windows kernel-mode driver handles objects in memory. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

Recommendation. Most customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.

For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update at the earliest opportunity using update management software, or by checking for updates using the Microsoft Update service.

See also the section, Detection and Deployment Tools and Guidance, later in this bulletin.

Knowledge Base Article

Affected and Non-Affected Software

The following software have been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, see Microsoft Support Lifecycle.

Why was this bulletin revised on March 27, 2013? Microsoft revised this bulletin to correct the workarounds: Prevent users from connecting to a USB device that has already been installed on the system and Disable the USB driver for a USB device that is not already installed on the system. The original workarounds included steps to block the connecting to and installation of USB storage devices. These steps have been removed from the workarounds because they are unnecessary.

I applied the original workarounds. Do I need to reapply the workarounds? No. Customers who have applied the original workarounds do not need to reapply them because the original workarounds block known attack vectors. However, since it is unnecessary to block the connecting to and installation of USB storage devices, Microsoft recommends these steps in the original workarounds be undone.

I applied the original "Prevent users from connecting to a USB device that has already been installed on the system" workaround.How do I undo the steps that disabled USB storage device functionality? Locate the backup file ("UsbStor_backup.reg ") created in the workaround. Perform the following command on the file:

Regedit /s UsbStor_backup.reg

I applied the original "Disable the USB driver for a USB device that is not already installed on the system" workaround. How do I undo the steps that disabled USB storage device functionality? Perform the following commands from a command prompt as an administrator:

I am using an older release of the software discussed in this security bulletin. What should I do?The affected software listed in this bulletin have been tested to determine which releases are affected. Other releases are past their support life cycle. For more information about the product lifecycle, see the Microsoft Support Lifecycle website.

Customers who require custom support for older software must contact their Microsoft account team representative, their Technical Account Manager, or the appropriate Microsoft partner representative for custom support options. Customers without an Alliance, Premier, or Authorized Contract can contact their local Microsoft sales office. For contact information, see the Microsoft Worldwide Information website, select the country in the Contact Information list, and then click Go to see a list of telephone numbers. When you call, ask to speak with the local Premier Support sales manager. For more information, see the Microsoft Support Lifecycle Policy FAQ.

Vulnerability Information

The following severity ratings assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin's release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the March bulletin summary. For more information, see Microsoft Exploitability Index.

An elevation of privilege vulnerability exists when Windows USB drivers improperly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full administrative rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2013-1285.

Mitigating Factors

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

In a default configuration, an unauthenticated attacker could only exploit this vulnerability if they have physical access to the system.

Workarounds

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

Prevent users from connecting to a USB device that has already been installed on the system

Use this workaround to block the attack vector through a USB device that has already been installed on the system. You can change the registry to make sure that the device does not work when the user connects to the computer.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Impact of workaround. Users cannot install a USB RNDIS device on the computer.

Create backups of the registry keys. Backup copies can be made using a managed deployment script with the following commands:

FAQ

What is the scope of the vulnerability?This is an elevation of privilege vulnerability.

What causes the vulnerability?The vulnerability is caused when the Windows kernel-mode driver improperly handles objects in memory.

What is the Windows kernel? The Windows kernel is the core of the operating system. It provides system-level services such as device management and memory management, allocates processor time to processes, and manages error handling.

What might an attacker use the vulnerability to do?An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full administrative rights.

How could an attacker exploit the vulnerability?An attacker could exploit the vulnerability by inserting a malicious USB device into the system.

What systems are primarily at risk from the vulnerability?Workstations are primarily at risk.

What does the update do?The update addresses the vulnerability by correcting the way that the Windows kernel-mode driver handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.

An elevation of privilege vulnerability exists when Windows USB drivers improperly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full administrative rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2013-1286.

Mitigating Factors

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

In a default configuration, an unauthenticated attacker could only exploit this vulnerability if they have physical access to the system.

Workarounds

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

Prevent users from connecting to a USB device that has already been installed on the system

Use this workaround to block the attack vector through a USB device that has already been installed on the system. You can change the registry to make sure that the device does not work when the user connects to the computer.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Impact of workaround. Users cannot install a USB RNDIS device on the computer.

Create backups of the registry keys. Backup copies can be made using a managed deployment script with the following commands:

FAQ

What is the scope of the vulnerability?This is an elevation of privilege vulnerability.

What causes the vulnerability?The vulnerability is caused when the Windows kernel-mode driver improperly handles objects in memory.

What is the Windows kernel? The Windows kernel is the core of the operating system. It provides system-level services such as device management and memory management, allocates processor time to processes, and manages error handling.

What might an attacker use the vulnerability to do?An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full administrative rights.

How could an attacker exploit the vulnerability?An attacker could exploit the vulnerability by inserting a malicious USB device into the system.

What systems are primarily at risk from the vulnerability?Workstations are primarily at risk.

What does the update do?The update addresses the vulnerability by correcting the way that the Windows kernel-mode driver handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.

An elevation of privilege vulnerability exists when Windows USB drivers improperly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full administrative rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2013-1287.

Mitigating Factors

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

In a default configuration, an unauthenticated attacker could only exploit this vulnerability if they have physical access to the system.

Workarounds

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

Prevent users from connecting to a USB device that has already been installed on the system

Use this workaround to block the attack vector through a USB device that has already been installed on the system. You can change the registry to make sure that the device does not work when the user connects to the computer.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Impact of workaround. Users cannot install a USB RNDIS device on the computer.

Create backups of the registry keys. Backup copies can be made using a managed deployment script with the following commands:

FAQ

What is the scope of the vulnerability?This is an elevation of privilege vulnerability.

What causes the vulnerability?The vulnerability is caused when the Windows kernel-mode driver improperly handles objects in memory.

What is the Windows kernel? The Windows kernel is the core of the operating system. It provides system-level services such as device management and memory management, allocates processor time to processes, and manages error handling.

What might an attacker use the vulnerability to do?An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full administrative rights.

How could an attacker exploit the vulnerability?An attacker could exploit the vulnerability by inserting a malicious USB device into the system.

What systems are primarily at risk from the vulnerability?Workstations are primarily at risk.

What does the update do?The update addresses the vulnerability by correcting the way that the Windows kernel-mode driver handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.

Yes, you must restart your system after you apply this security update.

Removal information

WUSA.exe does not support uninstall of updates. To uninstall an update installed by WUSA, click Control Panel, and then click Security. Under Windows Update, click View installed updates and select from the list of updates.

Yes, you must restart your system after you apply this security update.

Removal information

WUSA.exe does not support uninstall of updates. To uninstall an update installed by WUSA, click Control Panel, and then click Security. Under Windows Update, click View installed updates and select from the list of updates.

Yes, you must restart your system after you apply this security update.

Removal information

To uninstall an update installed by WUSA, use the /Uninstall setup switch or click Control Panel, click System and Security, and then under Windows Update, click View installed updates and select from the list of updates.

Yes, you must restart your system after you apply this security update.

Removal information

To uninstall an update installed by WUSA, use the /Uninstall setup switch or click Control Panel, click System and Security, and then under Windows Update, click View installed updates and select from the list of updates.

Yes, you must restart your system after you apply this security update.

Removal information

To uninstall an update installed by WUSA, use the /Uninstall setup switch or click Control Panel, click System and Security, click Windows Update, and then click Installed updates and select from the list of updates.

Yes, you must restart your system after you apply this security update.

Removal information

To uninstall an update installed by WUSA, use the /Uninstall setup switch or click Control Panel, click System and Security, click Windows Update, and then click Installed updates and select from the list of updates.

Note A registry key does not exist to validate the presence of this update.

Other Information

Acknowledgments

Microsoft thanks the following for working with us to help protect customers:

Andy Davis of NCC Group for reporting the Windows USB Descriptor Vulnerability (CVE-2013-1285)

Andy Davis of NCC Group for reporting the Windows USB Descriptor Vulnerability (CVE-2013-1286)

Andy Davis of NCC Group for reporting the Windows USB Descriptor Vulnerability (CVE-2013-1287)

Microsoft Active Protections Program (MAPP)

To improve security protections for customers, Microsoft provides vulnerability information to major security software providers in advance of each monthly security update release. Security software providers can then use this vulnerability information to provide updated protections to customers via their security software or devices, such as antivirus, network-based intrusion detection systems, or host-based intrusion prevention systems. To determine whether active protections are available from security software providers, please go to the active protections websites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.

Disclaimer

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions

V1.0 (March 12, 2013): Bulletin published.

V1.1 (March 27, 2013): Revised bulletin to remove workaround steps for disabling USB mass storage devices because these steps are not necessary to block known attack vectors. For more information, see Update FAQ.

V1.2 (July 9, 2013): Bulletin revised to announce a detection change in the Windows Vista packages for the 2807986 update to correct a Windows Update reoffering issue. This is a detection change only. Customers who have already successfully updated their systems do not need to take any action.